Digital audio anti-shake and delay transmission preventing audio amplifier
Technical Field
The present invention relates to audio amplifiers, and more particularly, to an audio amplifier for preventing digital audio jitter and delay transmission.
Background
Digital Signal Processing (DSP) is an emerging discipline that involves many disciplines and is widely used in many fields. Since the 60s of the 20 th century, digital signal processing technology has been developed and developed rapidly with the rapid development of computer and information technologies. Digital signal processing has been in widespread use in the field of communications and the like for over twenty years. The digital signal processing is to collect, transform, filter, estimate, enhance, compress, identify, etc. the signal in digital form by using computer or special processing equipment to obtain signal form meeting the needs of people.
The current art is evolving with a new and new trend, and industries such as digital musical instruments, live broadcasting, etc. are evolving rapidly, and in this field, a large number of DSP audio processing devices are required to be used, and at the same time, it is also common to integrate the DSP in the audio amplifier. At present, a DSP module is generally in a fixed frequency working mode, and delay instability is caused when a larger data volume is encountered, so that larger delay and jitter are generated. In order to overcome this situation, the main frequency of DSP devices needs to be continuously increased, but the chip with high main frequency generally has higher cost, and at the same time, the chip can generate larger heat during the operation of high main frequency, which leads to overheating of the chip and reduced service life.
Disclosure of Invention
In order to solve the above problems, the present invention provides a digital audio anti-jitter and delay-transmission-preventing audio amplifier, which comprises an input interface, an output interface, a DSP audio processing module, a digital-to-analog conversion amplifying module, a delay calculating module, a delay feedback module, an over-frequency controller and an anti-jitter processing module;
the input interface is used for connecting with a sound source, acquiring original audio data, and sending the original audio data to the DSP audio processing module;
The DSP audio processing module processes the audio, wherein the processing comprises gain, distortion, EQ adjustment and reverberation increase;
the digital-to-analog conversion amplifying module performs digital-to-analog conversion on the audio data to obtain an analog audio signal, amplifies the analog audio signal and outputs the amplified analog audio signal to the output interface;
The delay calculation module acquires the delay delta t between the input interface and the output interface and sends the delay to the delay feedback module, wherein the delay feedback module sends the delay delta t to the over-frequency controller, and the over-frequency controller is connected with the DSP audio processing module and the anti-shake processing module;
The over-frequency control module is used for controlling the over-frequency performance of the DSP processing chip, and the anti-shake processing module is used for generating an anti-shake reverse signal and outputting the anti-shake reverse signal to the output interface, and the anti-shake reverse signal is overlapped with the signal output by the digital-to-analog conversion amplifying module, so that the anti-shake effect is realized.
The input interface is provided with a marking module which is used for superposing a feature code on the original audio data acquired by the input interface, wherein the feature code comprises a time stamp, and the feature code corresponds to a feature frequency after being digital-to-analog converted;
The feature codes are sent to the DSP audio processing module and then output to the digital-to-analog conversion amplifying module, converted into analog signals and sent to the output interface;
The delay calculating module obtains the characteristic frequency corresponding to the characteristic code from the output interface and calculates the time of the characteristic code, so that the delay delta t of the characteristic code, which is output to the digital-to-analog conversion amplifying module and is transmitted to the output interface after passing through the DSP audio processing module, is calculated.
The delay feedback module acquires the delay delta t obtained by the delay calculation module in real time, generates a time-dependent change curve of the delay delta t, namely a delay change curve, and sends the delay change curve to the over-frequency controller;
The method comprises the steps of obtaining a time delay change curve by an over-frequency controller, carrying out time integration, wherein the time range of integration is from t 1 before the current time to the current time, inputting an integration result D into an adjustment model, calculating over-frequency f corresponding to different D values in the adjustment model, obtaining the over-frequency f by the over-frequency controller and sending the over-frequency f to a DSP audio processing module, and enabling the DSP audio processing module to work according to the over-frequency f, so that the frequency conversion work of the DSP audio processing module is realized, and delay transmission is reduced.
The modeling method of the regulation model comprises the following steps:
Inputting the same section of audio signal into a DSP audio processing module, carrying out single processing and superposition mixing processing by using four processing modes of gain, distortion, EQ adjustment and added reverberation in the DSP audio processing module under the basic working frequency, obtaining 15 groups of delay Deltat 0 under different processing conditions by using a delay calculation module, adjusting the working frequency of the DSP audio processing module to enable the DSP audio processing module to work under different over-frequency f states, and obtaining 15 groups of delay Deltat under different processing conditions under different frequencies by using the delay calculation module to obtain 15 groups of f-Deltat curves;
Setting the delay of the DSP audio processing module in each combination as Deltat 1 when the DSP audio processing module works at the highest super-frequency, calculating a coefficient M= (Deltat 0-△t1)/△t1; the M value represents the sensitivity of the delay of the DSP audio processing module to the working frequency in different working modes, and the larger the M value is, the more sensitive the delay is, and the more obvious the delay reduction is realized by improving the frequency;
The adjustment model is provided with a threshold D 0, when D > D 0, the frequency Deltaf= (k/M). F 0 is increased, and when D < D 0, the frequency Deltaf= (k/M). F 0 is decreased, wherein f 0 is the adjustment step size.
The anti-shake processing module acquires analog audio data from the digital-to-analog conversion amplifying module, and segments the analog audio data by taking the audio loudness A 0 as a threshold value, when the actual loudness A of the analog audio data is larger than A 0, the part with the loudness exceeding A 0 is inverted, when the actual loudness A of the analog audio data is smaller than A 0, the part with the loudness smaller than A 0 is duplicated, and the duplicated loudness is adjusted to be A 0 -A;
the delay feedback module acquires the delay Deltat obtained by the delay calculation module in real time, generates a time-dependent change curve of the delay Deltat, namely a delay change curve, and sends the delay change curve to the anti-shake processing module;
The anti-shake processing module calculates variance of Deltat in a period from the current moment to the current moment from the front t 1, when the variance exceeds a threshold value, the anti-shake processing module outputs the anti-shake audio and the copied audio to the output interface for superposition, and when the variance is smaller than the threshold value, the anti-shake processing module does not output the anti-shake audio and the copied audio to the output interface for superposition.
The DSP audio processing module is further provided with a phase processing module, and the phase processing module is connected between the DSP audio processing module and the digital-to-analog conversion amplifying module and is used for performing phase processing on the audio data processed by the DSP audio processing module.
The phase processing module comprises a relative phase measurer, a phase discriminator, a loop filter, a high-frequency VCO, a synchronous frequency divider and an I2S clock and data phase rearrangement module;
the Data are input into an I2S clock and Data phase rearrangement module, and the I2S clock and Data phase rearrangement module outputs three Data of BCK, WCK and Data after rearrangement;
The audio BCK and the WCK are input to a relative phase measurer and an I2S clock and data phase rearrangement module, meanwhile, one branch of the WCK is input to a phase discriminator, the phase discriminator is output to a loop filter, the loop filter is output to a high-frequency VCO, the high-frequency VCO is output to a synchronous frequency divider and a relative phase measurer, and the synchronous frequency divider is output to the phase discriminator;
the relative phase measurer takes the rising edge of the WCK as a standard, tests the relative phases of the WCK and the BCK, and sends the quantized phase error value to the I2S clock and data phase rearrangement module to realize the relative rearrangement of the clock and data phases.
The rising edge of the BCK clock signal is used as a building reference of the latch signal, the BCK clock signal is aligned to the centers of the rising edge and the falling edge of the Data signal when the phases are arranged, the effective edge of the latch clock is built after the Data is stable, and the Data is ensured not to be influenced by jitter and discrete of circuit delay.
The high frequency VCO is set to 16 times BCK frequency.
The beneficial effects of the invention are as follows:
The invention is provided with an over-frequency controller and an anti-shake processing module, wherein the over-frequency controller acquires a delay change curve, performs time integration, the time range of integration is from t 1 before the current time to the current time, inputs an integration result D into an adjusting model, calculates over-frequency f corresponding to different D values in the adjusting model, acquires the over-frequency f and sends the over-frequency f to a DSP audio processing module, and the DSP audio processing module works according to the over-frequency f, thereby realizing the variable frequency work of the DSP audio processing module, reducing delay transmission, and being particularly suitable for application scenes requiring real-time feedback and extremely high delay requirements such as live broadcasting, musical instrument playing and the like.
The anti-shake processing module is used for generating an anti-shake reverse signal and outputting the anti-shake reverse signal to the output interface, and the anti-shake reverse signal is overlapped with the signal output by the digital-to-analog conversion amplifying module, so that an anti-shake effect is realized. When the delay is unstable, unstable jitter is generated due to the volume of sound played by the loudspeaker caused by the unstable delay, and in order to restrain the jitter, an anti-jitter processing module is used for generating an anti-phase signal or a copy signal when the delay is unstable and is overlapped with the original audio playing, so that the overlarge volume is reduced, the overlarge volume is increased, and the anti-jitter effect is achieved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the disclosed subject matter, are incorporated in and constitute a part of this specification. The drawings also set forth implementations of the disclosed subject matter and, together with the detailed description, serve to explain the principles of the implementations of the disclosed subject matter. No attempt is made to show structural details of the disclosed subject matter in more detail than is necessary for a fundamental understanding of the disclosed subject matter and its various ways of practice.
FIG. 1 is a diagram of the overall architecture of the present invention;
FIG. 2 is a schematic diagram of a phase processing module according to the present invention;
Fig. 3 is an input/output diagram of the phase processing module according to the present invention.
Detailed Description
The advantages, features and manner of attaining the stated objects of the invention will become apparent from the description to follow, and from the drawings.
Example 1:
Referring to fig. 1, a digital audio anti-shake and delay-preventing audio amplifier includes an input interface, an output interface, a DSP audio processing module, a digital-to-analog conversion amplifying module, a delay calculating module, a delay feedback module, an over-frequency controller, and an anti-shake processing module;
the input interface is used for connecting with a sound source, acquiring original audio data, and sending the original audio data to the DSP audio processing module;
The DSP audio processing module processes the audio, wherein the processing comprises gain, distortion, EQ adjustment and reverberation increase;
the digital-to-analog conversion amplifying module performs digital-to-analog conversion on the audio data to obtain an analog audio signal, amplifies the analog audio signal and outputs the amplified analog audio signal to the output interface;
The delay calculation module acquires the delay delta t between the input interface and the output interface and sends the delay to the delay feedback module, wherein the delay feedback module sends the delay delta t to the over-frequency controller, and the over-frequency controller is connected with the DSP audio processing module and the anti-shake processing module;
The over-frequency control module is used for controlling the over-frequency performance of the DSP processing chip, and the anti-shake processing module is used for generating an anti-shake reverse signal and outputting the anti-shake reverse signal to the output interface, and the anti-shake reverse signal is overlapped with the signal output by the digital-to-analog conversion amplifying module, so that the anti-shake effect is realized.
The input interface is provided with a marking module which is used for superposing a feature code on the original audio data acquired by the input interface, wherein the feature code comprises a time stamp, and the feature code corresponds to a feature frequency after being digital-to-analog converted;
The feature codes are sent to the DSP audio processing module and then output to the digital-to-analog conversion amplifying module, converted into analog signals and sent to the output interface;
The delay calculating module obtains the characteristic frequency corresponding to the characteristic code from the output interface and calculates the time of the characteristic code, so that the delay delta t of the characteristic code, which is output to the digital-to-analog conversion amplifying module and is transmitted to the output interface after passing through the DSP audio processing module, is calculated.
The delay feedback module acquires the delay delta t obtained by the delay calculation module in real time, generates a time-dependent change curve of the delay delta t, namely a delay change curve, and sends the delay change curve to the over-frequency controller;
The method comprises the steps of obtaining a time delay change curve by an over-frequency controller, carrying out time integration, wherein the time range of integration is from t 1 before the current time to the current time, inputting an integration result D into an adjustment model, calculating over-frequency f corresponding to different D values in the adjustment model, obtaining the over-frequency f by the over-frequency controller and sending the over-frequency f to a DSP audio processing module, and enabling the DSP audio processing module to work according to the over-frequency f, so that the frequency conversion work of the DSP audio processing module is realized, and delay transmission is reduced.
The modeling method of the regulation model comprises the following steps:
Inputting the same section of audio signal into a DSP audio processing module, carrying out single processing and superposition mixing processing by using four processing modes of gain, distortion, EQ adjustment and added reverberation in the DSP audio processing module under the basic working frequency, obtaining 15 groups of delay Deltat 0 under different processing conditions by using a delay calculation module, adjusting the working frequency of the DSP audio processing module to enable the DSP audio processing module to work under different over-frequency f states, and obtaining 15 groups of delay Deltat under different processing conditions under different frequencies by using the delay calculation module to obtain 15 groups of f-Deltat curves;
Setting the delay of the DSP audio processing module in each combination as Deltat 1 when the DSP audio processing module works at the highest super-frequency, calculating a coefficient M= (Deltat 0-△t1)/△t1; the M value represents the sensitivity of the delay of the DSP audio processing module to the working frequency in different working modes, and the larger the M value is, the more sensitive the delay is, and the more obvious the delay reduction is realized by improving the frequency;
The adjustment model is provided with a threshold D 0, when D > D 0, the frequency Deltaf= (k/M). F 0 is increased, and when D < D 0, the frequency Deltaf= (k/M). F 0 is decreased, wherein f 0 is the adjustment step size.
The anti-shake processing module acquires analog audio data from the digital-to-analog conversion amplifying module, and segments the analog audio data by taking the audio loudness A 0 as a threshold value, when the actual loudness A of the analog audio data is larger than A 0, the part with the loudness exceeding A 0 is inverted, when the actual loudness A of the analog audio data is smaller than A 0, the part with the loudness smaller than A 0 is duplicated, and the duplicated loudness is adjusted to be A 0 -A;
the delay feedback module acquires the delay Deltat obtained by the delay calculation module in real time, generates a time-dependent change curve of the delay Deltat, namely a delay change curve, and sends the delay change curve to the anti-shake processing module;
The anti-shake processing module calculates variance of Deltat in a period from the current moment to the current moment from the front t 1, when the variance exceeds a threshold value, the anti-shake processing module outputs the anti-shake audio and the copied audio to the output interface for superposition, and when the variance is smaller than the threshold value, the anti-shake processing module does not output the anti-shake audio and the copied audio to the output interface for superposition.
Example 2:
The DSP audio processing module is also provided with a phase processing module, and the phase processing module is connected between the DSP audio processing module and the digital-to-analog conversion amplifying module and is used for performing phase processing on the audio data processed by the DSP audio processing module.
Referring to fig. 2-3, the phase processing module includes a relative phase measurer 5, a phase detector 1, a loop filter 2, a high frequency VCO3, a synchronous frequency divider 4, and an I2S clock and data phase rearrangement module 6;
The Data is input into the I2S clock and Data phase rearrangement module 6, and the I2S clock and Data phase rearrangement module 6 outputs three Data of BCK, WCK and Data after rearrangement;
The BCK and the WCK of the audio source are input to a relative phase measurer 5 and an I2S clock and data phase rearrangement module 6, and a branch of the WCK is input to a phase discriminator 1, the phase discriminator 1 is output to a loop filter 2, the loop filter 2 is output to a high-frequency VCO3, the high-frequency VCO3 is output to a synchronous frequency divider 4 and the relative phase measurer 5, and the synchronous frequency divider 4 is output to the phase discriminator 1, so that the phase discriminator 1, the loop filter 2, the high-frequency VCO3 and the synchronous frequency divider 4 form a loop phase-locked frequency synthesizer to generate a high-frequency multiplication clock signal for phase quantization measurement, and the clock is synchronous with the WCK;
The relative phase measurer 5 tests the relative phases of the WCK and the BCK by taking the rising edge of the WCK as a standard, and sends the quantized phase error value to the I2S clock and data phase rearrangement module 6 to realize the relative rearrangement of the clock and data phases.
The rising edge of the BCK clock signal is used as a building reference of the latch signal, the BCK clock signal is aligned to the centers of the rising edge and the falling edge of the Data signal when the phases are arranged, the effective edge of the latch clock is built after the Data is stable, and the Data is ensured not to be influenced by jitter and discrete of circuit delay.
The high frequency VCO3 is set to 16 times BCK frequency.
The above description is merely of the preferred embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily think about the changes or substitutions within the technical scope of the present invention, and the changes or substitutions are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.